ORANGE RESEARCH A-PEEL-ING

These are some things you can do with an orange: Peel it and eat it, juice it and drink it, cook it in a sauce and serve it over roast duck.

Here is one thing Dr. Doyle Chastain can do: Extract a substance to kill infectious bacteria.

Chastain, a Titusville internal medicine specialist, and a team of collaborators at Creighton University in Omaha, Neb., are using a compound found in the peel of citrus fruit to destroy a range of bacteria.

The substance has been found effective against the microbes that cause dental plaque, strep throat, toxic shock syndrome and Legionnaire's disease.

"I grew up in the middle of an orange grove over in Lake Wales and always wanted to do something with citrus products," Chastain said on Friday as he presented his findings at the last day of an infectious disease convention in Orlando.

"We've found it to be rapidly lethal to bacteria."

Dr. Eugene Sanders of the Center for Research in Anti-Infectives and Biotechnology at Creighton said there are more than 100 substances known as terpenes in the oil of citrus fruit peel. Terpenes have been used in perfume, cleaning solvents and even in some experimental anti-cancer drugs.

The terpene Chastain and Sanders are studying is d-limonene, which they chemically alter to produce an antibacterial substance called RBE-limonene.

Chastain, who has received government patents on the compound, said the citrus-based antimicrobial can be used in health care and in agriculture.

An antibacterial ointment could be used in hospitals to help limit the spread of infectious bacteria by doctors and nurses. Medical personnel often transmit bacteria from one patient to another when they do not adequately disinfect their hands.

At very low concentrations, Chastain said, RBE-limonene can kill the organism that causes tuberculosis as well as the organisms that cause canker development in tomatoes and oranges.

He and his Nebraska colleagues presented results of their studies at the 34th Interscience Conference on Antimicrobial Agents and Chemotherapy. They say because of RBE-limonene's killing capability it may be useful as a disinfectant to clean floors and other surfaces.

Dr. Robert Braddock, a professor of food science at the University of Florida's Citrus Research and Education Center in Lake Alfred, said terpenes have long been used as a component in pine cleaners.